Early Transition Metal Complexes of Triphosphorus Macrocycles

Abstract

The reactions of 1,5,9-triethyl-1,5,9-triphosphacyclododecane, [12]aneP3Et3, with first-row transition metal halides MCl3 [M = Ti (1), V (2), and Cr (3)] or their THF adducts are reported. The oxidation of 2 gives the complex ([12]aneP3Et3)V(O)Cl2 (4). This is the first example of a phosphane ligand that is trans to a vanadyl moiety. Also reported are VIII (5) and CrIII (6) complexes of the pendant ether macrocycles [12]aneP3(C2H4OEt)3 and 12[ane]P3(C3H6OMe)3 respectively. The complexes 1−6 have been characterised crystallographically and represent a rare class of phosphane complexes of these metals. The paramagnetic d1 compounds are characterised by EPR and ENDOR spectroscopy, simulation of which gives valuable structural information of these species in frozen solution. With [12]aneP3Et3, NbIII and NbIV chlorides give air-sensitive materials which could not be fully characterised although by comparison with compound 4, EPR and ENDOR spectroscopy indicate the principal oxidation product to be ([12]aneP3Et3)Nb(O)Cl2 (7). (© Wiley-VCH Verlag GmbH, 69451 Weinheim, Germany, 2002)